package com.wugui.datax.admin.filter;

import com.alibaba.fastjson.JSON;
import com.baomidou.mybatisplus.extension.api.R;
import com.wugui.datax.admin.exception.TokenIsExpiredException;
import com.wugui.datax.admin.util.JwtTokenUtils;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.web.authentication.www.BasicAuthenticationFilter;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Collections;

/** Created by jingwk on 2019/11/17 */
public class JWTAuthorizationFilter extends BasicAuthenticationFilter {

  public JWTAuthorizationFilter(AuthenticationManager authenticationManager) {
    super(authenticationManager);
  }

  @Override
  protected void doFilterInternal(
      HttpServletRequest request, HttpServletResponse response, FilterChain chain)
      throws IOException, ServletException {

    String tokenHeader = request.getHeader(JwtTokenUtils.TOKEN_HEADER);
    // 如果请求头中没有Authorization信息则直接放行
    if (tokenHeader == null || !tokenHeader.startsWith(JwtTokenUtils.TOKEN_PREFIX)) {
      chain.doFilter(request, response);
      return;
    }
    // 如果请求头中有token，则进行解析，并且设置认证信息
    try {
      SecurityContextHolder.getContext().setAuthentication(getAuthentication(tokenHeader));
    } catch (TokenIsExpiredException e) {
      // 返回json形式的错误信息
      response.setCharacterEncoding("UTF-8");
      response.setContentType("application/json; charset=utf-8");
      response.getWriter().write(JSON.toJSONString(R.failed(e.getMessage())));
      response.getWriter().flush();
      return;
    }
    super.doFilterInternal(request, response, chain);
  }

  // 这里从token中获取用户信息并新建一个token
  private UsernamePasswordAuthenticationToken getAuthentication(String tokenHeader)
      throws TokenIsExpiredException {
    String token = tokenHeader.replace(JwtTokenUtils.TOKEN_PREFIX, "");
    boolean expiration = JwtTokenUtils.isExpiration(token);
    if (expiration) {
      throw new TokenIsExpiredException("登录时间过长，请退出重新登录");
    } else {
      String username = JwtTokenUtils.getUsername(token);
      String role = JwtTokenUtils.getUserRole(token);
      if (username != null) {
        return new UsernamePasswordAuthenticationToken(
            username, null, Collections.singleton(new SimpleGrantedAuthority(role)));
      }
    }
    return null;
  }
}
